<!DOCTYPE html>
<html>
    <head lang="en">
        <meta charset="UTF-8">
        <TITLe></TITLe>
        <style>
          /*  h2:nth-child(odd){
                background-color: blueviolet;
            }*/
            h2:nth-of-type(odd){
                background-color: brown;
            }
            h2:nth-of-type(even){
                background-color: chocolate;
            }
        </style>
    </head>
    <body>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
        <h2>标题</h2>
    
        <p>发动快速减肥       </p>
    </body>
</html>